Erro ao colocar a imagem

import 'package:flutter/material.dart';

class Forms extends StatefulWidget {
  const Forms({super.key});

  @override
  State<Forms> createState() => _FormsState();
}

class _FormsState extends State<Forms> {
  TextEditingController nameController = TextEditingController();
  TextEditingController dificultyController = TextEditingController();
  TextEditingController imageController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Nova tarefa'),
      ),
      body: Center(
        child: Container(
          height: 650,
          width: 375,
          decoration: BoxDecoration(
            color: Colors.black12,
            borderRadius: BorderRadius.circular(10),
            border: Border.all(width: 3),
          ),
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: TextFormField(
                  controller: nameController,
                  textAlign: TextAlign.center,
                  decoration: const InputDecoration(
                    border: OutlineInputBorder(),
                    hintText: 'Nome',
                    fillColor: Colors.white70,
                    filled: true,
                  ),
                ),
              ),
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: TextFormField(
                  controller: dificultyController,
                  textAlign: TextAlign.center,
                  decoration: const InputDecoration(
                    border: OutlineInputBorder(),
                    hintText: 'Dificuldade',
                    fillColor: Colors.white70,
                    filled: true,
                  ),
                ),
              ),
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: TextFormField(
                  onChanged: (text) {
                    setState(() {
                      imageController = imageController;
                    });
                  },
                  controller: imageController,
                  textAlign: TextAlign.center,
                  decoration: const InputDecoration(
                    border: OutlineInputBorder(),
                    hintText: 'Imagem',
                    fillColor: Colors.white70,
                    filled: true,
                  ),
                ),
              ),
              Container(
                height: 100,
                width: 72,
                decoration: BoxDecoration(
                  color: Colors.blue,
                  borderRadius: BorderRadius.circular(10),
                  border: Border.all(width: 2, color: Colors.blue),
                ),
                child: ClipRRect(
                  borderRadius: BorderRadius.circular(10),
                  child: Image.network(
                    imageController.text,
                    fit: BoxFit.cover,
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}